Stacking system for paperboard blanks

ABSTRACT

APPARATUS FOR STACKING ALTERNATE STACKS OF CORRUGATED PAPERBOARD BLANKS DISCHARGED FROM A BLANK-FORMING MACHINE FACEUP AND FACEDOWN TO REDUCE WARPING COMPRISING AN INTERMITTENLY ROTATING TRANSVERSE STORAGE CONVEYOR MEANS FOR LRECEIVING AND TEMPORARILY STORING STACKS OF BLANKS IN FACEUP POSITION FROM AN IN-LINE CONVEYOR ADJACENT THE BLANK-FORMING MACHINE, AN INVERTER FOR SEQUENTIALLY RECEIVING STACKS FROM THE STORAGE CONVEYOR AND INVERTING ALTERNATE STACKS TO A FACEDOWN POSITION ON A RISING CONVEYOR COMPRISING A GUIDE FOR DIRECTING THE STACKS INTO A SUBSTANTIALLY VERTICAL POSITION WITH THE STACK RESTING ON ITS LEADING EDGE ON THE RISING CONVEYOR WHERE A PIVOTING FINGER CARRIED BY THE RISING CONVEYOR ENGAGES THE BOTTOM EDGE OF A FIRST STACK ON THE CONVEYOR TO ADVANCE IT ALONG THE CONVEYOR THEREBY POSITIONING THE FIRST STACK FACEUP, AN INVERTING LEVER ADJACENT THE UNDERSIDE OF A SUBSEQUENT STACK INTERMITTENLY OPERABLE TO ENGAGE THE UNDERSIDE SURFACE OF THIS SECOND STACK TO PIVOT IT ABOUT ITS BOTTOM EDGER SO THAT IT DESCENDS ONTO THE RISING CONVEYOR WITH ITS UNDERSIDE UP, FIRST AND SECOND ADVANCING FINGERS FOR SEQUENTIAL ENGAGEMENT WITH THE TRAILING EDGES OF THE FIRST AND SECOND STACKS TO ADVANCE THEM ALONG THE RISING CONVEYOR, A STACKER FOR RECEIVING STACKS OF BLANKS FROM THE RISING CONVEYOR AND STACKING THEM ONE UNDER THE OTHER TO FORM A PILE OF BLANKS COMPRISING A LIFTING CONVEYOR INCLUDING A STOP FOR POSITIONING EACH OF THE STACKS, MEANS FOR RAISING THE LIFTING CONVEYOR, WITH THE STACK THEREON, A DISTANCE SLIGHTLY GREATER THAN THE HEIGHT OF THE STACKS, A SUPPORT FOR ENGAGING THE BOTTOM FACE OF THE LIFTED STACK TO MAINTAIN THE STACK IN ITS LIFTED POSITION, MEANS FOR LOWERING THE LIFTING CONVEYOR TO RECEIVE ANOTHER STACK FOR REPEATING THE FOREGOING LIFTING OPERATION, AND MEANS ROTATING THE LIFTING CONVEYOR IN ITS UPPERMOST POSITION WHEN THE PILE OF BLANKS REACHES A SELECTED HEIGHT TO DISCHARGE THE PILE ON A SKID OR OTHER CONVEYOR FOR FURTHER HANDLING.

United States Patent [72] inventor Mirrea Calistrat Baltimore, Md. [211App]. No. 810,868

Nov. 27, 1968 Division of Ser. No. 666,605. Sept. 11, 1967, Pat. No.3.447.696.

June 28, 1971 Koppers Company, inc.

[221 Filed [45] Patented [73] Assignee [541 STACKING SYSTEM FORPAPERBOARD BLANKS 2 Claims, 13 Drawing Figs.

Primary E.tnminerRobert G. Sheridan Atlorneys-0scar B. Brum back, BoyceC. Dent and Olin E.

Williams ABSTRACT: Apparatus for stacking alternate stacks of corrugated paperboard blanks discharged from a blank-forming machine faceupand facedown to reduce warping comprising an intermittently rotatingtransverse storage conveyor means for receiving and temporarily storingstacks of blanks in faceup position from an in-line conveyor adjacentthe blankforming machine; an inverter for sequentially receiving stacksfrom the storage conveyor and inverting alternate stacks to a facedownposition on a rising conveyor comprising a guide for directing thestacks into a substantially vertical position with the stack resting onits leading edge on the rising conveyor where a pivoting finger carriedby the rising conveyor engages the bottom edge of a first stack on theconveyor to advance it along the conveyor thereby positioning the firststack faceup, an inverting lever adjacent the underside of a subsequentstack intermittently operable to engage the underside surface of thissecond stack to pivot it about its bottom edge so that it descends ontothe rising conveyor with its underside up, first and second advancingfingers for sequential engagement with the trailing edges of the firstand second stacks to advance them along the rising conveyor; a stackerfor receiving stacks of blanks from the rising conveyor and stackingthem one under the other to form a pile of blanks comprising a liftingconveyor including a stop for positioning each of the stacks, means forraising the lifting conveyor, with the stack thereon, a distanceslightly greater than the height of the stack, a support for engagingthe bottom face of the lifted stack to maintain the stack in its liftedposition, means for lowering the lifting conveyor to receive anotherstack for repeating the foregoing lifting operation, and means rotatingthe lifting conveyor in its uppermost position when the pile of blanksreaches a selected height to discharge the pile on a skid or otherconveyor for further handling.

PATENTEU JUN28 1911 SHEET 02 0F PATEN TEU JUN28 ml SHEET 03 0FPATENTEUJUNZBlQ?! 3587.830

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INVENTOR. F I 6 M/PCEA CAL/STRAT his PATENTEU JUN28|971 SHEET 08 0FINVENTOR. M/RCEA LAL ISTRA T PATENTED JUN28 r91:

SHEET 11 OF M d w A INVENTOR. MIRCEA CAL ISTPAT STACKING SYSTEM FORPAPERBOARD BLANKS This is a division application Ser. No. 666,605, filedSept. 11, 1967 now Pat. No. 3,447,696.

BACKGROUND OF THE INVENTION 1. Field of the Invention This inventionrelates generally to material or article handling and more particularlyto article piling or arranging apparatus.

2. Description of the Prior Art Corrugated paperboard blank-formingapparatus, commonly known as a corrugator, forms a continuous web ofcorrugated paperboard. Usually this web is longitudinally split into aplurality of parallel widths and each width is then cut laterally toform blanks of the material for making corrugated cartons such as boxes.The longitudinally advancing blanks are collected in stacks on adelivery conveyor which then discharges them transversely to the path ofblank travel for manual stacking into piles on a skid or other conveyor.

Despite constant efforts to improve the quality of box blanks thusproduced, the blanks still have a tendency to curl or warp, usually in adirection lateral to the web path. Warped blanks are difficult toprocess by further processing machinery. To reduce the amount of warp inthe blanks, it is customary to stack them in large piles of smallerstacks of which smaller sacks are alternately placed faceup andfacedown. In this manner, the warped portions of one stack oppose thewarped portions of an alternate stack so that the weight of the piletends to flatten the blanks.

Another inconvenience exists in that the advancing parallel adjacentblanks tend to become misaligned on the discharge conveyor so that theindividual blanks of adjacent stacks become interlaced. Thus, theattendants are required to manually separate these piles into discretestacks before alternate ones can be inverted.

Letchworth Pat. No. 3,297,174discloses apparatus for inverting alternatesmall stack of blanks. The Letchworth apparatus receives the stacks ofblanks from the corrugator on a plurality of conveyor delivery beltswhich are parallel but are at different levels so that one series ofblanks can be placed on another to form a larger stack which isthereafter inverted.

The parallel delivery belts of Letchworth require individual heightadjustment for supporting the parallel advancing blanks whose width mayvary from order to order. A disadvantage of this arrangement is that theparallel streams of blanks exiting from the cutoff portion of thecorrugator are frequently interlaced. Therefore, it is difficult for theblanks to drop to different levels as described by Letchworth. It isalso observed that it would be difficult to maintain the height of thefinal pile since it is formed by adding stacks to the top of the pile.Finally, turning alternate stacks of very large blanks 180 in onecontinuous motion requires considerable energy because of the large airresistance encountered by the blanks during such movement.

SUMMARY The present invention provides apparatus for automaticallyforming a pile of alternately inverted stacks of blanks which pile maybe of unlimited height. The apparatus is adaptable for use inconjunction with existing delivery conveyors without the need forcomplex adjustments. The apparatus includes a transverse storageconveyor adapted to receive stacks of blanks from a corrugator deliveryconveyor; an inverting apparatus for receiving consecutive individualstacks of blanks from the storage conveyor in a manner to stand thestacks on their leading edge, including an offsetting device foroffsetting alternate ones of the stacks relative to the other ones ofthe stacks across their length, and a first pivoting means for pivotinga first stack about its upstanding trailing edge to position the stackon a rising conveyor with its top faceup and a second pivoting means forpivoting a second stack about its leading edge to position the stack onthe rising conveyor with its top facedown; and a stacking means forreceiving alternately inverted stacks from the rising conveyor andforming them in a pile one under the other by a lifting means forlifting each stack consecutively into engagement with a pile supportmeans, the lifting means operable to discharge a pile of blanks ofselected height onto subsequent processing apparatus.

The above and further objects and novel features of the invention willappear more fully from the following detailed description when the sameis read in connection with the accompanying drawings. It is to beexpressly understood, however, that the drawings are not intended as adefinition of the invention but are for the purpose of illustrationonly.

DESCRIPTION OF THE DRAWINGS In the drawings wherein like parts aremarked alike:

FIG. 1 is a diagrammatic front elevation of a conventional deliveryconveyor illustrating the usual discharge of interlaced blanks;

FIG. 2 is a diagrammatic side elevation of an embodiment of the storageand loading conveyors and inverting mechanism illustrating stacks storedon the conveyor and a second stack being pivoted toward a top facedownposition on the rising conveyor;

FIG. 3 is a diagrammatic side elevation of an embodiment of the risingconveyor and stacking mechanism illustrating a pile of alternatelyinverted stacks of blanks being formed;

FIG. 4 is a plan view of FIG. I;

FIG. 5 is a plan view of FIG. 2;

FIG. 6 is a plan view of P10. 3;

FIG. 7 is a partial view of the inverting mechanism of FIG. 2illustrating a first stack being pivoted toward a top faceup position onthe rising conveyor;

FIG. 8 is a section view taken along the line VIII-VIII of FIG. 2illustrating an offset mechanism for laterally offsetting alternatestacks of blanks;

FIG. 9a is an elevational view of a portion of the rising conveyorillustrating the types of pivoting fingers and advancing fingers used topivot a first stack of blanks and advance both first and second stacksof blanks;

FIG. 9b is a plan view in partial cross section of one of the pivotingfingers of FIG. 9a illustrating its connection to the chains used on therising conveyor;

FIG. 10 is a partial view of the stacking mechanism of FIG. 3illustrating a squaring mechanism for aligning the stacks prior tolifting them to form the pile;

FIG. 11 is a schematic illustration of the sequence of pivoting thestacks in the inverting mechanism into alternate faceup and facedownpositions; and

FIG. 12 is a schematic diagram of the controls used for controlling thefunctions of the invention.

THE PREFERRED EMBODIMENT In the manufacture of corrugated blanks, a webof corru' gated paperboard is formed and then slit into a number ofparallel streams of desired width. These streams are subsequently cuttransversely to form parallel streams of blanks. The cutting operation,by its nature, inherently has a tendency to skew the blanks so that theyare not exactly parallel to the flow of blanks. Accordingly, overlappingof the blanks between the parallel stream occurs. This overlapping iscommonly known as interlacing. Stacks of interlaced blanks areillustrated in FIGS. 1 and 4.

Referring now to FIGS. 1 and 4, piles of interlaced blanks A and B andshingled blanks C and D (a portion of one blank resting upon the nextadjacent lower blank) are shown preparatory. to lateral discharge from aconventional delivery conveyor, generally designated 10, of a corrugator(not shown). Delivery 10 may be of the type shown in Lopez Pat. No.3,079,150 which includes belts 12 for advancing the blanks downstream inshingled fashion where they are temporarily halted by a gate 14. Beyondgate 14, delivery 10 includes a plurality of longitudinally mountedrollers at a lower elevation than belts 12. When gate 14 is removed fromthe leading edges of the shingled blanks C and D, they are advanced bybelts 12 causing them to fall one on top of the other upon rollers 16 toform piles A and B. A backstop 18 is pro vidcd to halt the forwardprogress of the blanks and is adjustable upstream and down toaccommodate the length of blanks being handled. Hereinafter, the length"of the blanks on stacks refers to their longitudinal dimension along thedelivery as viewed in FIG. 4.

When piles A and B reach a selected height, gate 14 is moved tointercept the flow of blanks C and D. Thereafter, rollers 16 are drivento discharge the piles A and B upon a storage conveyor assemblygenerally designated 20. When pile B is completely clear of delivery 10,the foregoing process is repeated.

Although only two parallel streams of blanks are shown, it is notuncommon to have the initially formed web slit into four and sometimesas many as seven streams. The split web is usually divided into an equalnumber of narrower webs of which one-half are guided into an uppercutoff knife and the other half into a lower cutoff knife. The shingledblanks C and D are discharged from one of the knives. Another delivery10 is provided to handle the discharge from the other knife. Either orboth deliveries 10 may be provided with the present invention which isillustrated herein to handle four streams from each delivery at maximumcorrugator speed and more at lesser corrugator speeds.

STORAGE CONVEYOR ln accordance with the invention, the blanks comingfrom the delivery conveyor 10 are received by a storage conveyor 20. Thelength of storage conveyor assembly 20 exceeds the width of deliveryconveyor 10 so that regardless ofthe number of piles on delivery 10,conveyor 20 is capable of receiving all of them.

The function of conveyor assembly 20 is to store the stacks receivedfrom delivery 10 and load them one at a time into the invertingmechanism 22 where stack A will be pivoted into faceup position andstack B will be pivoted into facedown position. Hereinafter, the face"of the stack refers to its top surface as it is discharged from conveyor10. The underside" of the stack refers to its bottom surface as it isdischarged from conveyor 10.

Conveyor assembly 20 includes a storage conveyor 24 and a loadingconveyor 26. Both conveyors 24 and 26 are intermittently drivensimultaneously. However, when conveyor 24 is not driven, it is capableof freewheeling whereas conveyor 26 will remain stationary. Thus, it canbe seen that stack A will be loaded into inverter 22 upon rotation ofconveyor 26 and, since conveyor 24 also rotates, stack B will moveforward into the position previously occupied by stack A thereby leavingconveyor 24 clear to receive subsequent stacks from delivery 10 when itis rotated for discharging. These subsequent stacks will advance uponthe freewheeling conveyor 24 by momentum induced by rollers 16 of thedelivery 10 until they rest against the stack B being held in stationaryposition by conveyor 26. In this manner, the timing of conveyor assembly20 is independent of the timing of the discharge from delivery 10, theonly requirement being that conveyor 20 discharges the stacks fasterthan it receives them as otherwise the stacks coming in from delivery 10would shove the stack A off.

As mentioned above, conveyors 24 and 26 are driven simultaneously. Thus,stack A, for example, advances beyond conveyor 26 and falls intoinverter 22. As stack A falls into inverter 22, the interlacing ofblanks between stacks A and B is broken leaving stack B as a discretestack on conveyor 26. The interlacing of the stacks is broken when thecenter of stack A passes over the end of conveyor 26, which causes thetrailing edge of stack A to rise, and falls into inverter 22. Thus, itcan be seen that the bending occurring between the stacks as stack Afalls into the inverter breaks the interlacing. This is advantageoussince merely attempting to break the interlacing by pulling the stacksapart in a straight line is often ineffective because blanks near thetop of the stacks tend to follow one another.

Storage conveyor 24 adjacent the discharge side of delivery 10 receivespiles of blanks A and B therefrom. Conveyor 24 comprises spaced frameportions 28a, 28b and 28c between which a plurality of rollers 30a and30b are bearing mounted in the conventional manner at an elevationsubstantially equal to the elevation of rollers 16 of delivery 10. Frameportion 28b is located near the center between frame portions 280 and28c to support the inboard ends of rollers 30a and 30b. The onlydifference between rollers 30a, 30b is their length as illustrated. Bysupporting them near the center, there is less tendency for them to sag.If desired, rollers 30a, 30b may have identical lengths.

Rollers 30a, 30b are driven at the desired interval of time by a pair ofdriven endless belts 32 positioned under the rollers, one of which isadjacent either side of frame portion 28b. Belts 32 encircle pulleywheels 34 mounted for rotation with pulley shafts 36a and 36b which arebearing mounted between frame portions 28a, 28b and 28c in a fashionsimilar to rollers 30a, 30b. One of shafts 28b, HO. 5, has an extension38 extending through frame portion 280 upon which is mounted a chainsprocket 40. A motor 42 is mounted in a known manner to frame portion280 and has an output shaft 44 upon which is mounted a chain sprocket46. A roller chain 48 encircles sprockets 40 and 46 for driving thepulley shafts 36a, 36b. The pulley shafts 36a and 36b are connectedwhere they are supported by frame portion 28b so that both belts 32 aredriven thereby.

Rollers 30a, 30b are driven by raising the upper run of belts 32 intofrictional engagement with their lower surfaces. To raise belts 32, abelt lifting bar 50 is provided beneath the upper runs of the beltswhich lifts the upper run against the rollers. Lifting bars 50 arepivotably mounted to frame portions 52 by levers 54 having conventionalpin connections 55 for attaching the levers to the bars and to the frameportions. One of levers 54 for each lifting bar 50 has an extension 56for connection with an air operated ram 58 pivotably connected to frameportion 28b. Conventional clevis connections 60 may be used to connectthe extensions 56 to the rams and the rarns to the frame portions.

As best illustrated in F IG. 2, as rams 58 are activated, they willextend and pivot extensions 56 about their pin connections therebyraising lifting bars 50 to the position shown by the dotted lines. Inthis latter position, belts 32 are pressed into driving engagement withrollers 30a, 30b. Motor 42 runs continuously. Rams 58 are simultaneouslyenergized by a signal from inverting mechanism 22, as will be laterexplained, to advance the stacks A and B with stack A being loaded intothe inverting mechanism.

LOADING CONVEYOR Loading conveyor assembly 26 is adapted to dischargestack A, as illustrated in FIG. 2, into inverter 22 and simultaneouslyplace stack B into the position previously occupied by A. Conveyor 26comprises a plurality of endless belts 62 spaced sideby-side across thewidth of the assembly and surrounding pulley wheels 64 secured forrotation on shafts 66 and 68. Shaft 66 is bearing mounted between frameportions 28a, 28c and drive shaft 68 is bearing mounted between frameportions 70a, 70b. Shaft 68 extends beyond frame portion 70b and has aconventional pneumatically energized clutch 72 mounted thereon. Clutch72 may be, for example, a Model LW, made by Horton Manufacturing Co.,Minneapolis, Minn., which includes an integrally mounted V-belt sheave74. Drive shaft 68 is driven through clutch 72 by a motor 76 having anoutput shaft 78 upon which a V-belt sheave 80 is mounted for rotation,the sheaves 74 and 80 being connected by V-belt 82. Motor 76 isconveniently mounted to frame portion 70b. Preferably, a speed reducer(not shown) is placed between clutch 72 and shaft 68 in the known mannerso that clutch 72 can be run at high speed by a conventional high speedmotor.

Motor 76 runs continuously. Clutch 72 is selectively energized by asignal from inverter 22, as will be later explained. When clutch 72 isenergized, belts 62 are rotated and stack A advances generallyhorizontally until its center of gravity passes beyond the return ofbelts 62 around pulleys 64. At this time, stack A pivots about pulleys64 and drops, leading edge downward, into inverter 22. Simultaneously,rams 58 have been activated and accordingly stack B advances ontoconveyor 26 until it trips a pneumatic valve 84 which deactivates rams58 and clutch 72.

Shaft 68 also extends beyond frame portion 70a and has a conventionalpneumatically energized shaft-mounted brake 86 mounted thereon and heldagainst rotation in the known manner. Brake 86 may be, for example, aModel K diaphragmtype made by Horton Manufacturing Co., Minneapolis,Minn. Brake 86 is energized when valve 84 is tripped by an advancingstack so that belts 62 cease rotating immediately, as clutch 72 isdeenergized, to prevent the stack from advancing too far beyond thepulleys 64 on shaft 68.

INVERTER AND OFFSETTING ASSEMBLIES Inverter assembly 22 receivesindividual stacks of blanks and inverts alternate ones of the stacks toa facedown position upon a rising conveyor assembly 90. The remainingstacks are placed on conveyor 90 in a faceup position.

Inverter 22 also offsets alternate stacks in a lateral direction asillustrated in FIG. 8. This offset condition contributes to ease ofhandling of the stacks in subsequent processing operations, providing agripping surface which the attendants may use in moving the stacks.

As best illustrated in FIG. 2, a stack B is inverted to a facedownposition by pivoting the stack B about its leading edge, as shown by thedotted lines. Pivoting is accomplished by an inverting lever 92 adjacentthe bottom face of stack B. After stack B has been laterally offset,lever 92 is actuated to pivot the stack about its leading edge so thatit falls facedown upon conveyor 90. Thereafter, stack B is advancedalong the conveyor by an advancing finger 94 and stack A (now on theconveyor 26) is discharged into inverter 22 by loading conveyor 26.

Stack A, FIG. 7, is pivoted about its trailing edge by a roller finger96, as shown by the dotted lines so that it falls faceup on risingconveyor 90. Thereafter, stack A is advanced by a subsequent advancingfinger 98.

FIG. 11 illustrates, in panelsthrough the inverting sequence of fourstacks A, B, C and D. The stacks are lettered and the heavy lineadjacent the face of the stacks indicates the relative face positions ofthe stacks during operation of inverter 22 and rising conveyor 90.Certain of the roller and advancing fingers are disengaged whenextra-width stacks are being handled. This feature will be subsequentlydescribed. Coincidentally, reading panels@,@,@and vertically shows thestacks A, B, C and D to be alternately inverted to faceup and facedownpositions.

Inverter assembly 22, FIGS. 2 and 8, comprises side guides in the formof upright angles 100 and 102 for receiving the stacks as they fall fromloading conveyor 26. Each of the guides has a side leg 104 for engagingthe ends of the stacks and a bottom leg 106 engaging the underside ofthe stacks to support them in an upright position. Slide block 108secured to leg 106 of guide 100 and mounting block 110 secured to leg106 of guide 102 support the guides on a pair of support rods 112.

OFFSETTING ASSEMBLY Support rods 112, FIG. 8, are slidably mounted inbrackets 114a and 114b provided on frame portions 70a, 70b. Mountingblock 110 is secured in a convenient manner to rods 112. A pneumatic ram116 is connected in a conventional manner to both mounting block 110 andto bracket 114b, so that, when ram 116 is actuated, block 110, andconsequently guide 102, moves laterally with respect to bracket 1141;.

Guide 100 is secured to slide block 108 which is free to slide alongrods 112. A base block 118, similar to mounting block 110, is movablymounted on rods 112 inboard of slide block 108. Base block 118 is lockedagainst one of rods 112 by a clamp screw 120. A pneumatic ram 122 isconnected in a conventional manner to both base block 118 and slideblock 108 so that, when ram 122 is actuated, block 108, being slidableon rods 112, moves laterally with respect to base block 118, carryingguide 100 with it. Base block 118 can be positioned and clamped alongrods 112 to place guide 100, through ram 122, in the correct positionfor acting on the stacks. In this manner, adjustment is provided tocompensate for stacks of various lengths.

FIG. 8 is a section taken along lines VIII-VIII of FIG. 2 except thatthe stacks are pictured as all standing on end to better illustrate themanner in which they are offset. Thus, the stacks are shown entering theinverter 22 with their lateral edges or ends in substantial alignment,it being understood that some ofthe individual blanks may be slightlyaskew.

The right-hand portion of FIG. 8 illustrates the position of guides 100,102 prior to and after acting upon stack A. The left-hand portionillustrates the position of the guides prior to and after operating onstack B. The extreme left-hand portion illustrates the relative lateraloffset positions of stacks A and B after the offsetting operation.

Referring to the right-hand portion of FIG. 8, guide 102 is in theposition shown prior to receiving stack A from conveyor 26. Leg 104 ofguide 102 is spaced a short distance from the edge of stack A as itenters inverter 22. Leg 104 of guide 100 is in the position indicated bythe dotted lines, being placed in this position by the extension of ram122 and being spaced a short distance from the edge of stack A. Afterstack A has entered inverter 22, ram 122 is actuated thereby pullingguide 100 against stack A and moving it against guide 102. Ram 122 isimmediately actuated in the reverse direction returning the guide 100 toits original position. Accordingly, stack A is unrestrained so that itmay be pivoted about its trailing edge by roller finger 96 and thus fallfaceup on rising conveyor 90.

After stack B has entered inverter 22, as shown in the lefthand portionof FIG. 8, guide 100 is again actuated in the same manner as for stack Athereby moving stack B against guide 102, guide 102 being in theposition indicated by the dotted lines. Simultaneously, ram 116 isactuated which moves rods 112 to the left a shown by the dotted lines.Base block 118, being clamped to rods 112, moves to the left pushingslide block 108, via ram 122, to the position shown. In this manner,stack B is squared against guide 102 and also offset to the left withrespect to stack A. when stack B reaches its offset position, ram 116 isretracted and ram 122 is extended to return guide 100 and 102 to theirprevious positions ready to receive subsequent stack A.

INVERTER ASSEMBLY After each stack A or B has been offset, stack A isinverted to a faceup position and stack B is inverted to a facedownposition. As previously mentioned, stack A is pivoted about its trailingedge by a roller finger 96 and then advanced along rising conveyor byadvancing finger 98. Stack B is pivoted about its leading edge byinverting lever 92 and then advanced along rising conveyor 90 byadvancing finger 94.

The inverting lever 92 is pivotably supported between a clevis bracket124 by a pin 126 passing through lever 92 and bracket 124. Bracket 124is secured to rising conveyor 90. Lever 92 includes an upstanding legportion 128 which, in its retracted position, is on the same plane withthe leg portions- 102 of guides and 102. That is, leg 128 liesimmediately behind the bottom face of a stack A or B in the inverter 22.Lever 92 includes a short leg 130 formed at a right angle with leg 128and connected to a pneumatic ram 132 by a conventional pin connection134. Ram 132 is pivotably secured to rising conveyor 90 by a similar pinconnection 136. After a stack B in the inverter 22 has been offset, aspreviously described, ram 132 is actuated thereby pivoting lever 92about pin 126 as shown by the dotted lines in FIG. 2. Upstanding leg 128pushes against stack B thereby pivoting it about its leading edge sothat it falls facedown on conveyor 90.'Thereafter, advancing finger 94is moved forward to engage the trailing edge (previously the leadingedge) of stack B and advance it along conveyor 90. Simultaneously, ram132 is retracted to return lever 92 to its original position.

To invert a stack A in inverter 22 to a faceup position on conveyor 90,a roller finger 96' is advanced against the lower portion of the back ofstack A after the stack has been offset. A small roller 136 carried byfinger 96 pushes against the stack thereby moving its leading edgeforward and letting its trailing edge slide down the leg portions 106 ofguides 100 and 102. The end result is that stack A is generally pivotedabout its trailing edge until it rests on conveyor 90. As the stackslides down onto conveyor 90, finger 96 continues to advance along theconveyor, with the small roller 136 rolling along the bottom of thestack, until finger 96 is forward of stack A. Thereafter, advancingfinger 94 is moved forward to engage the trailing edge of the stack andadvance it along conveyor 90.

RISING CONVEYOR Rising an advancing conveyor 90 advances the offset andinverted stacks to an entry conveyor 138 from which the stacks aredischarged into'a stacker portion 140. Conveyor 90 comprises a pluralityof stack supports 142a, b, c, and e extending substantially between alower sprocket shaft 144 and an upper sprocket shaft 146. As bestillustrated in FIGS. 2 and 3, supports 142 are mounted upon a pair ofcrossmember 148 which have their ends supported by longitudinallyextending frame members 150a, l50b secured to upstanding frame portions70a, 70b and 152a, 1521).

Sprocket shaft 144 is rotatably mounted between frame portions 70a, 70band has an extended portion 154 extending beyond frame portion 70b uponwhich is mounted a pulley wheel 156. A speed reducer 158 is mounted onframe portion 70b and carries a clutch 160 thereon, the clutch beingsubstantially identical to clutch 72 previously described. Clutch 160 isdriven by the rotation of speed reducer 158 which is in turn rotated bya pulley wheel 162 mounted thereon connected by a V-belt 164 to a pulleywheel 166 mounted on output shaft 78 of motor 76. An output pulley wheel168 on clutch 160 drives pulley wheel 156 through a V-belt 170 andthereby rotates sprocket shaft 144.

Upper sprocket shaft 146 is rotatably mounted between frame portions1720, 172b of entry conveyor 138. Pairs of roller chains 174 located inspaces provided between stack supports 142 encircle sprockets 176 and178 mounted respectively on the lower sprocket shaft 144 and uppersprocket shaft 146. The path traveled by the upper runs of chains 174carries them over sprockets 180 secured to pulley shaft 182 of entryconveyor 138 for driving shaft 182.

As best illustrated in FIGS. 9a and 9b, each pair of chains 174 carriesroller fingers 96 and advancing fingers 94 therebetween so that thefingers travel with the chains. Four kinds of fingers, 94, 96, 184, and186 are used. Each of the fingers includes a U-shaped body portion 183as viewed in FIG. 9a, having a lug portion 188 on each leg thereofextending beside the adjacent chain 174. Chain 174 includes a link 190extending upward so as to overlap lug portions 188. Pins 192 extendthrough holes provided in both the lugs 188 and links 190 to pivotablysupport the fingers to the chains. Pins 192 are retained by cotter pins194.

Fingers 94 and 184 also include lug portions 196 similar to and spacedfrom lugs 188 to overlap a subsequent link 190 in chain 174. Pins 192likewise connect lugs 196 to links 190 so that fingers 94 and 184 willnot pivot about pins 192 in lugs 188.

Fingers 96 and 186 include lug portions 198 extending beneath chains 174between which a roller 200 is carried by a pin 202 passing through theroller 200 and lugs 198. Pin 202 is retained by cotter pins 194. Thus,it can be seen that fingers 96 and 186 are free to pivot about pins 192in lugs 188 as indicated in the right-hand portion of FIG. 9a. Acounterweight 204 is secured between the legs of the U-shaped bodyportion of fingers 96 and 186 by a bolt 206 and a nut 208 clamping thelegs against the counterweight. The counterweight causes the stackengaging faces 210 of the fingers to lie substantially fiat with respectto the chains 174 as viewed to the extreme right of FIG. 9a.

Referring now to FIGS. 2 and 3, conveyor also includes a roller support212 beneath the upper run of each pair of chains 174 for engagingrollers 200 of fingers 96 and 186 to maintain the fingers in an uprightposition as viewed in FIG. 9a. However, roller supports 212 may belowered to the position shown by dotted lines in FIGS. 2, 3, 9a, and 11.When in the lowered position, fingers 96 and 186 will lie flat aspreviously explained.

Lowering of roller supports 212 is accomplished by pivotably supportingthem on frame members 1500, b. Pivot rods 214 are provided between framemembers 150a, 1501). Pivot rods 214 are provided between frame members1500, 150b with pivot arms 216 secured thereto in a position beneathroller supports 212. Pivot arms 216 are connected to the supports 212 bya conventional pin connection 218 which allows the supports to swivelwith respect to the pivot arms. Thus, when the pivot arms 216 arerotated clockwise, as viewed in FIGS. 2 and 3, the roller supports 212will be lowered to the position indicated by the dotted lines. Anoperating lever 220 is provided on one end of one of pivot rods 214 forrotating the rod. A suitable clamp (not shown) is provided to lock thepivot rod in the desired position when the supports 212 are in eitherthe raised or lowered position.

Thus, it can be seen that when the supports 212 are in the lowerposition, fingers 96 and 186 will traverse the upper run of chains 174in a fiat position, as viewed in FIG. 9a, since rollers 200 do notcontact the supports 212. However, when supports 212 are in the raisedposition, rollers 200 will flip the fingers 96 and 186 into an uprightposition as they approach the supports 212. A lead-in portion 222 onsupports 212 aid in pivoting the fingers to an upright position. Fingers96 and 186 merely hang free from pins 192 during the traverse of chains174 along the lower run between the sprockets 176 and 178.

The length of rising conveyor 90 is made to accommodate the widest stackto be handled. As viewed in FIGS. 2 and 3,

which may conveniently be joined to give a complete picture of conveyor90, stack A is being discharged onto entry conveyor 138 as stack B isbeing inverted to fall facedown on conveyor 90. Thus, sufficient spacemust be allowed between finger 98 and the finger 94 approaching inverter22. For example, if the maximum width stack to be handled is 5 feet, aspace of about 6 feet is required between the fingers. However, if thestack width is less than half the maximum width, that is, 2% feet orless, obviously two stacks can be accommodated between fingers 98 and94. This explains the reason for providing some of the fingers withrollers 200 supported by roller supports 212.

FIG. 11 illustrates stacks of 2% feet or less being processed. Forstacks A and C two fingers are required; roller finger 96 to invert thestack to a faceup position and advancing finger 94 to advance the stackalong the conveyor. On the other hand, stacks B and D require only anadvancing finger 186 to advance it along the conveyor. Thus, threefingers are required for each set of stacks AB and C-D. Since a set ofnarrow stacks can be accommodated simultaneously on conveyor 90,obviously another set of three fingers can be carried on the lower runof chains 174. Accordingly, a total of six fingers are provided at theproper sequential spacing on chains 174. However, appropriate ones ofthe fingers may be lowered to an inoperative position by lowering rollersupports 212 so that only three fingers remain upright for handlingstacks wider than 2% feet.

Obviously, lowering three adjacent fingers will leave three fingersupright at a short spacing. Therefore, selected ones of the fingers arelowered to leave three fingers upright at the required spacing for widestacks. FIG. 11 illustrates in dotted lines those fingers to be loweredwhen wide stacks are handled.

As previously mentioned, finger 96 is provided with a roller 136 topermit the finger to pass beneath stack A after the stack has beeninverted thereby. Finger 184 is likewise provided with a roller 136.Roller 136 is carried between upstanding lug portions 224 of fingers 96and 184 by a pin 226 passing through both the roller 136 and lugs 224.Cotter pins 194 retain pin 226, as illustrated in FIG. 9b.

Although the foregoing arrangement of conveyor 90 has been described forwide stacks of from 2% to feet and narrow stacks of 2% feet and less,obviously, the proportions may be designed to handle other size stackswhich may be manufactured.

Conveyor 90 normally runs continuously. However, in the event that astack is not present in loading conveyor 26, a signal is provided todisengage clutch 160 so that conveyor 90 is not driven. The signal alsoenergizes a brake 228 (similar to brake 86) carried by an extension 230on sprocket shaft 144 extending beyond frame portion 700. The signalwill be discussed further in the control portion of the specification.Brake 228 is used to stop the chains 174 immediately after the signal isreceived so that the fingers will remain in timed relation to loadingconveyor 26. Otherwise, a stack could be loaded in inverter 22 with thefingers in the wrong position to maintain the inverting sequence.

ENTRY CONVEYOR Entry conveyor 138 removes stacks of blanks from conveyor90 at a slightly faster speed than they are traveling so that they moveaway from the advancing finger to allow the finger to clear the stack asit passes over sprocket 180 and thereafter around spro'cket 178. Thestacks are also made level for entry into stacker 140.

Conveyor 138 comprises a pulley shaft 182 mounted for rotation betweenframe portions 1520, 152b and a pulley shaft 232 mounted for rotationbetween frame portions 234a and 234b, the latter frame portions beingcommon to stacker 140. Pulley wheels 236 are mounted on shaft 182adjacent each of the sprockets 180 as shown in FIG. 6. Correspondingpulley wheels 238 are mounted on shaft 232. Endless belts 240 encirclecorresponding pairs of pulley wheels 236 and 238. Pulley wheels 236 aredriven by the rotation of shaft 182 which in turn driven by sprockets180 being rotated by chains 174. Sprockets 180 are somewhat smaller thanthe pulleys 236 so that the surface speed of belts 240 is greater thanthe velocity of the advancing fingers. An increase in speed of about 5percent is usually sufficient to allow the fingers to clear the stacksbeing advanced by the entry conveyor 138.

STACKER ASSEMBLY Stacker 140, FIG. 3, forms a pile of stacks receivedsequentially from entry conveyor 138 and discharges a pile of selectedheight to a conveyor, skid, or the like for subsequent processing. Thisfunction is accomplished by receiving each stack on a lifting conveyor242, raising the conveyor to lift the stack a predetermined distance,retaining the stack in its raised position by a holding device 244 underthe leading edge of the stack and a holding device 246 under thetrailing edge of the stack, lowering conveyor 242 to its originalposition to receive a subsequent stack, releasing the holding devices244, 246 to drop the raised stack onto the stack now rising on conveyor242, raising both stacks a predetermined distance and repeating theforegoing procedure until the pile reaches a height sufficient to trip alimit switch 248 which stops the whole machine preceding the stacker140. At this time, lifting conveyor 242 remains in its raised positionand is slowly rotated to discharge the pile onto a conveyor 250.Thereafter, conveyor 242 is lowered and the whole procedure is repeated.

The lifting conveyor portion 242 of stacker is positioned between frameportions 234a, 2341; and frame portions 252a, 252b. Conveyor 242comprises a pair of laterally spaced subframes 2540, 254b between whicha pair of pulley shafts 256, 258 are journaled for driven rotation.Pulleys 260 are spaced across and secured to the pulley shafts 256, 258as best illustrated in FIG. 6. Endless belts 262 encircle pulleys 260and have an upper run at the same level as belts 240 of entry conveyor238. A substructure 265 secures subframes 254a, 254b and also supportsidler rollers 266 under the upper run of belts 262.

A motor 268, secured to subframe 254b, is provided for driving belts262. A clutch 264, similar to clutches 72 and 160, is mounted on anextension 266 of pulley shaft 258 and includes a pulley wheel 269connected by a V-belt 270 to a pulley wheel 272 on output shaft 274 ofmotor 268. Motor 268 runs continuously but the belts 262 are rotatedonly when clutch 264 is energized. The belts 262 are rotated whenlifting conveyor 242 is in the lowered position to receive stacks fromentry conveyor [38. The belts continue to rotate until the stack reachesa backstop 276 fixed between frame portions 252a, 2521; at which timethe stack trips a valve 278 which deenergizes clutch 264. Simultaneouslywith stoppage of belts 262, conveyor 242 is lifted.

A valve 275 is mounted on frame portion 296 in a position to be trippedby subframe 254b. Valve 275 energizes clutch 264 to start belts 262rotating when conveyor 242 returns to its lowermost position.

A valve 277 is mounted to frame portion 234b in a position to be trippedby a cam 279 mounted on subframe 254b. The function of valve 277 is toretract the holding plates 308 and 310 from beneath the pile just priorto the stack being raised reaching them so that the pile descends only ashort distance. Valve 277 maintains the plates retracted until the stackbeing lifted is above them at which time the plates are extended beneaththe pile. Valve 277 is a conventional maintained contact-type, beingoperable only so long as it remains tripped by cam 279. Thus, cam 279has a long contact surface 281. Valve 277 is a single-direction-type sothat cam 279 does not actuate it during downward travel of liftingconveyor 242.

The subframes 254a, 254b are guided for vertical movement by V-notchedrollers 278 secured to frame portions 2340, 234b and 2520, 252b. TheV-notches in rollers 278 mate with corresponding V-portions 280 formedin the edges of subframes 254a, 254b.

Lifting of conveyor 242 is accomplished by a crank mechanism 282comprising a gearbox 284 driven by a continuously running motor 286connected thereto through a conventional shaft-mounted air clutch 288.The gearbox 284 has an output shaft 290 extending from opposite sidesthereof upon which are mounted driving arms 292. The driving arm 292 onone side of the gearbox is connected to a bellcrank 294 toward theupstream side of the stacker and the other driving arm is connected to abellcrank 294 toward the downstream side. The bellcranks 294 arepivotably supported on a crossmember 296 between frame portions 234 and252. Connecting links 298 connect bellcranks 294 to driving arms 292through conventional pin connections 300. Lifting arms 302 connect thebellcranks 294 to the subframes 254a, 2541) through pin connections 304.Thus, it can be seen, as best illustrated in FIG. 3, that rotation ofoutput shaft 290 pivots bellcranks 294 about their fulcrums 306 therebylifting the subframes 2540, 254b through the connecting links. Theproportions of crank mechanism 282 are easily calculated in the knownmanner to give the amount of vertical travel desired.

Clutch 288, previously referred to, is actuated by valve 278 (which alsostops belts 262) to elevate lifting conveyor 242 when the advancingstack has reached backstop 276. The clutch remains engaged until arms292 have made a complete revolution and, consequently, the conveyor 242is in its lowermost position. As the conveyor reaches the lowerposition, valve 275 is tripped which disengages the clutch 288. Switch278 is ready for triggering by another advancing stack to again stopbelts 262.

The input shaft 283 of gearbox 284 extends beyond the side opposite towhere it is connected to coupling 288 and has a shaft-mounted airbrake285 mounted thereon (similar to brake 228) for stopping rotation of theoutput shaft 290 of the gearbox.

It should be noted here that switch 248 not only stops the portion ofthe machine preceding the stacker, but also disengages clutch 288 andactuates brake 285 to stop lifting conveyor 242 in its uppermostposition. Simultaneously, switch 248 activates clutch 264 to start belts262 and signals motor 268 to run at half-speed to slowly discharge thepile onto conveyor 250.

After a stack has been received on conveyor 242 and belts 262 havestopped, the conveyor is lifted to an upper position. At this time,holding devices 244 and 246 are actuated. Holding device 244 includes anumber of support plates 308 extendable horizontally beneath the raisedstack to provide a support upon which the stacks may rest after thelifting conveyor is lowered. Holding device 246 includes similar supportplates 310.

Holding device 244 is supported on an upstreamdownstream adjustablesupport provided for longitudinally positioning plates 308 for thedifferent width stacks to be handled. The adjustable support comprisesupright stanchions 312a and 3l2b guided on spur toothed racks 314a and3l4b secured between frame portions 234a, 2341) and 252a, 252b. Guidingis accomplished by providing a tongue portion 316 along the bottom edgeof the stanchions which mates with corresponding grooves 318 formed inthe sides of racks 314a, 3l4b. This arrangement also prevents thestanchions 3120, 312b from tilting.

Stanchions 3121:, 31% are laterally connected by crossmembers 320 and322. To adjust holding device 244 towards backstop 276, spur gears 324are secured to stub shafts 326 rotatably mounted in stanchions 3120,312b so that the gears are in mesh with racks 314a, 3l4b. Stub shafts326 extend through stanchions 3121:, 312b and have sprockets 328 securedto their outermost ends. A cross-shaft 330 is rotatably mounted instanchions 312a, 3l2b at a height sufficient to permit a stack to passthereunder onto lifting conveyor 242. A sprocket 332 is secured to theoutermost ends of cross-shaft 330 beyond the stanchions. A roller chain334 encircles the sprockets 332, 334 on the stub-shafts and cross-shaftrespectively. A handwheel 336 is provided on one end of cross-shaft 330for turning the cross-shaft which in turn will rotate gears 324 alongracks 314a, 3l4b to position holding device 244. A conventionalshaft-lock (not shown) is provided on cross-shaft 330 adjacent handwheel336 to lock the stanchions in the position selected.

Support plates 308 of holding device 244 are moved into engagement withthe bottom of a lifted stack by a pneumatic ram 338 pivotably secured toa bracket 340 by a pin connection 342; the bracket 340 being secured tocrossmember 322. Each plate 308 rests on a support shaft 344 journaledbetween stanchions 3124, 312k. Each plate 308 is connected via pinconnection 346 to an associated lever 348 pivotably supported on across-shaft 350 rotatably mounted in brackets 352 secured to crossmember322. Ram 338 is connected to one of levers 348 by pin connection 354.All of levers 348 are keyed to cross-shaft 350 so that pivoting of thelever connected to the ram causes all the levers to pivot causing plates308 to move substantially horizontally into and out of engagement withthe stack.

Holding device 246 is constructed in a similar fashion to holding device244. Support plates 310 rest on a roller 357 journaled between frameportions 2520, 252b. Each plate is connected via pin connection 356 toan associated lever 358 pivotably supported on a cross-shaft 360rotatably mounted in brackets 362 secured to frame portions 252a, 252b.Ram 364 is pivotably supported by a pin connection 366 to a bracket 368which is secured to frame portion 370. Ram 364 is connected to one ofthe levers 358 by pin connection 372. Actuation of ram 364 moves all theplates 310 either into or out of engagement with the stack, dependingupon whether the ram is extended or retracted.

Stacker 140 also includes a squaring device 374 for urging a stack onlifting conveyor 242 into full engagement with backstop 276. Squaringdevice 274 operates in a similar fashion to holding device 244, as bestillustrated in FIG. 10. A pneumatic ram 376 is pivotably supported by apin connection 378 on a bracket 379 secured to crossmember 320. Levers380 are pivotably supported laterally adjacent to levers 348 on across-shaft 382 rotatably supported in brackets 384 secured tocrossmember 322. Each lever 380 has a squaring shoe 384 connectedthereto by a pin connection 386 which permits the shoe to swivel. Ram376 is connected to one of the levers 380 by a pin connection 388. Whenram 376 is retracted, the levers 380 assume the position shown by thedotted lines, leaving clearance for a stack to enter stacker 140. Whenram 376 is extended, shoes 384 are urged against the trailing edge ofthe stack to urge it into full engagement with backstop 276. After thestack is squared, ram 376 is immediately retracted so that the stack maybe lifted without interference.

Stacker 140 preferably includes a discharge roller 390 rotatablyjournaled between brackets 392a, 392b secured to frame portions 252b,252b. A continuously running motor 394, mounted to bracket 396 securedto frame portion 252b, is provided for driving roller 390. A sprocket298 on output shaft 400 of motor 394 is connected by a chain 402 to asprocket 404 provided on roller 390. Thus, as the pile is dischargedfrom stacker 140 by rotation of lifting conveyor 242, roller 390supports the pile and transports it to conveyor 250 for furtherhandling.

CONTROLS The controls for the complete machine are illustratedschematically in FIG. 12. For the most part, the controls are pneumaticalthough a completely electrical system will work equally well and maybe used if desired.

As illustrated herein, most of the valves used are contained in aconsole 406 supported by frame portion 408 as shown in FIG. 2. Acamshaft 410 is journaled in console 406 for actuating various ones ofthe valves used. Camshaft 410 is driven by a sprocket 412 mountedthereon connected by a chain 414 to a sprocket 416 mounted on speedreducer 158.

Referring now to FIG. 12, air pressure is supplied to manuallycontrolled valve 418 which has three operative positions a, b, and 0.Position a is used for narrow stacks, i.e., in the example previouslygiven, stacks up to 2% feet wide. Position b is the "off" positionwhereby the air supply is cut off and all air lines are vented toatmosphere. Position c is used for wide stacks, i.e., for stacks between2% and 5 feet in width.

Shuttle valve 420 is supplied with pressure from either of positions aor c of valve 418. Valve 420 supplies pressure to all nine maincam-actuated valves 422, 424, 426, 428, 430, 432, 434, 436, and 438.Each of these main valves is operated by a cam secured on camshaft 410which rotates once for each revolution of chains 174.

A manually controlled valve 440 controls the inverting sequence. Inposition a, all the wide stacks are inverted faceup on rising conveyorin position b, all the stacks are inverted facedown on rising conveyor90; and, in position 0, the stacks are inverted alternately faceup andfacedown on conveyor 90.

Microvalve 84, located on loading conveyor 26, is triggered by, that is,senses, a stack advanced to the loading position above inverter 22.

A manually controlled valve 442 is used to interrupt the offsettingfunction shown in FIG. 8.

The foregoing valves are conventional. For example, valves 418, 440 and442 may be three-position selector valves, Model 8771, such as made byRepublic Manufacturing Company, Cleveland, Ohio. Valves 84 and 278 maybe hair-trigger microvalves, Model HTW-40D, such as made by Mead FluidDynamics, Chicago, Illinois. Even numbered valves 422 through 438 may bethree-way roller cam-acutated springreturn, Model CWl3-25, made byParker-Hannifm, Des Plaines, lllinois. Valve 275 may be a four-way ModelCCl3-25 made by the same company. Valve 420 may be a shuttle-valve,Model OR-25, also made by Parker-Hannifin.

For a better understanding of the operation of the controls, assume thatconveyor 20 is empty, chains 174 are moving, and valves 422 and 424 arenot actuated. Pressure from valve 444 flows through valve 446 toactuator valve 448. Pressure from valve 448 actuates clutch 72 andreleases brake 86 and ram 58 so that belts 62 begin to move. Pressurefrom valve 444 also switches valve 450 from the position shown with noimmediate effect.

When cams 452 and 454 trigger either of valves 422 or 424 respectively,and still no stack is on belts 62, pressure from valves 422 or 424actuates valve 456 through valve 458. Pressure from valve 444 flowsthrough valve 456 and valve 460 and actuates valve 462 so that theclutch 160 for chains 174 is vented to atmosphere and brake 228 isactuated. Accordingly, chains 174 are stopped but belts 62 continue tomove. It should be noted that, for wide stacks, manual valve 418supplies pressure to valve 424 and, for narrow stacks, it suppliespressure to valve 422. 7

Now, assuming that chains 174 are stopped and a stack triggers sensingvalve 84, then valve 84 actuates valve 444. Port A-l, previously underpressure, is vented so that valve 450 is switched back to the positionshown. Pressure from port A-2 flows through valves 450 and 446 tomaintain valve 448 actuated so that belts 62 continue to move.

Because port A-l of valve 444 is vented, port -2 of valve 456 is alsovented. Because valve 456 is actuated, valve 462 is also vented, throughvalve 460, so that it is deactivated. Thus, clutch 160 is actuated andchains 174 begin to move. When chains 174 move, camshaft 410 is rotated,as previously described, and cam 452 releases valve 422 (or cam 454releases valve 424) so that valve 456 is deactivated and valve 462remains vented. Note than whenever valve 462 is under pressure, chains174 are stopped and when valve 462 is vented, chains 174 will move.

Movement of belts 62 loads the stack into inverter 22 and simultaneouslyreleases sensing valve 84. Valve 444 is thereby deactivated and pressureflows through its port A-l, and on through valve 446 to activate valve448 to keep belts 62 running. Valve 444 simultaneously activates pilotP-l of valve 450.

When a subsequent stack triggers sensing valve 84, valve 444 is actuatedand both ports of valve 446 are vented; one through valve 444 and theother through valve 450. Ac cordingly, valve 448 is deactivated andbelts 62 stop with the stack waiting to be loaded into inverter 22 asillustrated in 1 10.2.

While belts 62 are stopped and a stack is waiting to be loaded, chains174 continue to move. Valve 444 is activated, with its port Al vented.As camshaft 41!) rotates, cam 452 triggers valve 422 (or cam 454triggers valve 424) and pressure flows through valve 458 to activatepilot P-2 of valve 450. Pressure from port A2 of valve 444 flows throughvalve 450 and valve 446 to actuate valve 448 to energize clutch 72 andbelts 62 start to move. Although valve 456 is also activated, chains 174continue to move because port 0-2 of valve 456 is vented through valve444. As the stack falls into inverter 22, the sequence, previouslydescribed, is repeated wherein a subsequent stack triggers sensing valve84 that stops the belts 62, as previously described, which are againstarted at the proper time by either of cams 452 or 454.

The inverting ram 132 is actuated (extended) by valve 464. Valve 464 isactuated by either of valves 466 or 468 which can be actuated by any oneof valves 426, 428 or 4.30. Valve 426 is supplied with pressure onlyfrom position a of manual valve 418 which position is used for narrowstacks. Cam 470 for valve 426 has two lobes for actuating valve 426twice for each revolution of camshaft 410 thereby causing every otherstack to be inverted facedown. This results only when narrow stacks arebeing handled since, as illustrated in FIG. 11, four stacks are handledfor every complete revolution of chains 174.

Valve 428 is supplied with pressure only from position 0 of manual valve418 which position is used for wide stacks. Cam 472 for valve 428 hasonly one lobe for actuating valve 428 once for each revolution ofcamshaft 410 thereby causing every other stack to be inverted facedown.This results when wide stacks are handled since only two stacks arehandled for every complete revolution of chains 174.

Provision is made for inverting every other stack of wide stacks orinverting them all faceup or all facedown. Selector valve 440 controlsthis function. Accordingly, when selector valve 418 is in position 0 forwide stacks, valve 440 must also be positioned in position a, b or c forthe inverting sequence desired. Therefore, valve 428 is supplied withpressure from positions a or c of valve 440 when valve 418 is inposition c. Valve 430 is supplied with pressure from position a of valve440 when valve 418 is at position 0 so that all of the wide stacks areinverted faceup.

The offsetting function is accomplished by actuating both rams 116 and122. If no offset is desired, only ram 122 is actuated. For eachrevolution of chains 174, four offsets are required for narrow stacksand two offsets for wide stacks. Valves 432, 434, 436, and 438 are usedto control rams 116 and 122. Valves 432, 436 are actuated for narrowstacks; valves 434, 438 are actuated for wide stacks. Valve 474 actuatesram 122 with pressure supplied from valve 476. Valve 472 is actuated byeither valve 432 or 434. Either of valves 436 and 438 actuate valve 480through valve 478. Valve 478 actuates ram 116.

The stacker is controlled by microvalve 278 which is triggered by astack entering upon lifting conveyor 242 and a conventional electriclimit switch 248, mounted on frame portion 478, which is triggered bythe pile when it reaches the desired height. Switch 248 may bepositioned vertically along frame portion 478 at any desired interval toprovide piles of various heights.

When valve 278 is triggered, it actuates pilot valve 481 which stops theflow of pressure to valve 482 from valve 484 and the flow of pressure tovalve 486 from valve 488. Thus, clutch 264 is disengaged and liftingconveyor belts 262 stop; brake 285 is released and clutch 288 is engagedso that lifting conveyor 242 begins to rise. Simultaneously, ram 376 isactuated to activate the squaring device 374.

After rising conveyor 242 begins to rise, valve 275 is triggered bysubframe 254b moving upward away from it. This stops the flow ofpressure to valve 481 and instead supplies pressure to valve 486 whichreverses ram 376 to retract squaring device 374. Valve 275 remainsactivated until lifting conveyor 242 returns to its lower position.

Cam 279, carried on subframe 254b, triggers valve 277 as liftingconveyor 242 rises. Valve 277 actuates rams 338 and 364 which retractholding plates 308 and 310 thereby letting the pile fall upon theascending stack. The holding plates remain retracted until conveyor 242is in its uppermost position.

Provided the pile has not yet reached its preselected height fordischarge, the crank mechanism 282 continues to run so that conveyor 242returns to its lower position. In the uppermost of conveyor 242, thelower portion ofsurface 281 of cam 279 has passed valve 277, releasingit. When valve 277 is released, it actuates (extends) rams 338 and 364to place holding plates 308 and 310 under the lifted pile. As conveyor242 moves downward, the movement of cam 279 does not affect valve 277because the valve works only when triggered in a single direction. Asthe conveyor 242 moves downward, the pressure of the stacks againstvalve 278 is released. However, the conveyor 242 continues to movedownward because valve 275 will remain actuated until it is deactivatedby contact with subframe 254b. Thereafter, the cycle is repeated untilthe pile reaches the height at which it is to be discharged ontoconveyor 250.

Upon reaching the predetermined height, electric limit 248 is triggeredwhich in turn actuates solenoid valve 492. However, valve 277 is stillactuated by surface 281 of cam 279, and will remain so until cam surface281 clears valve 277, so that no change occurs. However, when valve 277is released by surface 281, pressure flows through it to valve 482through valves 492 and 484. This deactivates clutch 288 and actuatesbrake 285 to stop conveyor 242 in its uppermost position.Simultaneously, electric switch 248 signals motor 268 to run athalf-speed, clutch 264 being energized, to run belts 262 therebydischarging the pile onto driven roller 390 and thereafter onto-conveyor250. Valve 492 remains actuated until the stack is discharged at whichtime valve 482 is deactivated and the conveyor moves downward throughthe same cycle that occurred during normal stacking without discharge.

While conveyor 242 is stopped in its uppermost position for discharging,pressure flows through valves 277 and 492 to valve 462 through valve 460thereby stopping movement of chains 174. The chains remain motionlessthroughout the time the pile is being discharged.

The various valves used in the above control system are conventional andcommercially available. For example, valves 444, 464, 474, 480, 456,462, 448, 481, 486 and 482 may be pilot operated four-wayv spring returnpressure valves, Model CCl-25 made by Parker-Hannifin, Des Plaines,Illinois. Valve 450 may be a pilot operated four-way pressure returnpressure valve Model CCl2-25 made by the same company. Valve 492 is asolenoid operated four-way pressure valve Model CCJ l-25, also made byParker-Hannifin.

The various cams on camshaft 410 are preferably made angularlyadjustable about the camshaft so that the timing of the machine can beeasily altered if needed. Setscrews (not shown) can be used to clamp thecams to the shaft for this purpose.

From the foregoing description of the control system, it will beunderstood that the lobes of the cams are positioned at various anglesto each other in order that the valves may be actuated in the propersequence. Since some of the valves are actuated more than once duringeach operating cycle of chains 174, some of the cams have more than onelobe. For the preferred embodiment of the machine described herein, theangular position of the lobes on the cams is illustrated schematicallyin the top portion of FIG. 12. Although the cams continue to actuatetheir respective valves regardless of the length stacks being handled,some of the valves themselves are inoperative depending on the width ofthe stacks. Accordingly, S indicates that the cam and its associatedvalve are operative for narrow stacks; L indicates that the cam and itsassociated valve are operative for wide stacks.

OPERATION In operation gate 18 of delivery conveyor is positioned in aknown manner upstream or downstream to accommodate the length of theblanks forming the stacks. Thereafter, the guide 100 in the offsettingportion of inverter 22 is positioned by clamping slide-block 118 on rods112 as previously described. Leg 104 of guide 100 is preferablypositioned about 4 inches from the lateral end of the stack as it entersthe inverter 22.

If wide stacks are to be handled, roller supports 212 are lowered byturning handle 200 on rising conveyor 90 and clamping it in position.This causes the appropriate ones of the inverting and advancing fingersto become inoperative as previously described. For narrow stacks, rollersupports 212 remain in the raised position.

The next step is to adjust the longitudinal position of holding plates308 for the length of the stack being handled. This is done by rotatinghandwheel 336 on stacker 140 to move plates 308 toward or away frombackstop 276. The holding device 244, carrying plates 308, is thenlocked in position by clamping handwheel 336.

The height of the pile to be formed is selected and switch 248 is raisedor lowered accordingly and clamped on its support 478.

Thereafter, manual valve 418 is turned from off position b to either aposition for narrow stacks or 0 position for wide stacks. Manual valve440 is turned to position a if the stacks are to be all inverted faceup;to position b if all the stacks are to be inverted facedown; to position0 if alternate stacks are to be inverted facedown. Manual valve 440 isoperative only when wide stacks are processed, that is, at position 0 ofvalve 418. Narrow stacks are always alternately inverted. Manual valve478 is turned from the OFF position b to position c if offsetting of thestacks is desired; to position a if no offsetting is desired.

A master switch (not shown) is turned on to energize motors 42, 76, 268,286, and 394. At this time, the machine is operative and in condition toreceive stacks from delivery conveyor 10.

As the blanks are supplied in stacks from the corrugating deliveryconveyor 10, the stacks are received on storage conveyor 24. Conveyors24 and 26 are operated simultaneously to advance the stack to conveyor26 to convey the stacks to the position shown in FIG. 2. The conveyor 26is actuated again when chains 174 are at the correct position at whichpoint stack A and stack B are advanced simultaneously, but stack A isadvanced beyond the support provided by conveyor 26. The leading edge ofstack A is thus unsupported and tends to fall and its trailing edgetends to rise thereby separating any interlacing between the stacks.Stack A is received by inverter 22 and guided into an upright position.The guides and 102 are operated to laterally offset the stack. Stack Ais pivoted about its trailing edge by a pivoting finger carried on therising conveyor 90 so that it falls faceup on the conveyor. Thereafter,an advancing finger carried by the conveyor engages the trailing edgeand advances stack A along the conveyor. Meanwhile stack B on thestorage conveyor 24 has been advanced upon conveyor 26 to the positionpreviously occupied by stack A. At the proper interval of rotation ofchains 174 on conveyor 90, conveyor 26 will be rotated to load stack Binto inverter 22. Stack B is offset and then pivoted about its leadingedge by the inverting lever 92, so that i falls facedown upon conveyor90. Thereafter an advancing linger on chains 174 engages its trailingedge and advances it along conveyor 90. Meanwhile stack A, which haspreceded stack B, is received upon entry conveyor 138 which rotatesfaster than chains 174 so that the trailing edge of stack A advancesfaster than the advancing finger so that the finger will clear the stackas it begins its return along the lower run of chains 174. Entryconveyor 138 loads stack A into stacker 140. The lifting conveyor 242 ofstacker 140 is in its lower receiving position as stack A is loaded intothe stacker. Upon entering the stacker, stack A will trip a valve 278which simultaneously stops rotation of belts 262 of conveyor 242 andraises the lifting conveyor to an upper position. Upon reaching theupper position, supporting plates 308 and 310 are operated to engage theunderside of stack A to support it in the upper position. Conveyor 242is then returned to its lower position for receiving subsequent stack Bfrom entry conveyor 138. Stack B is then lifted toward the upperposition by conveyor 242. As the stack approaches stack A, thesupporting plates 308 and 310 are retracted from beneath stack A so thatstack A falls upon stack B. Conveyor 242 continues to rise therebylifting both stack A and stack B to the upper position whereupon supportplates 308 and 310 are again operated to engage the underside of stack Bto support both stacks A and B in the upper position. Conveyor 242 againreturns to its lower position for receiving a subsequent stack A. Theforegoing steps are repeated until the pile of stacks in stack 140reaches a height sufficient to trip limit switch 248. Limit switch 248is operative to stop the conveyor 242 in its uppermost position andsimultaneously rotate belts 262 of conveyor 242. This causes the pile ofblanks resting on the belts to be discharged to the left, as shown inFIG. 3, upon driven roller 390 which aids in advancing the pile toconveyor 250 for further handling.

The pile in stacker 140 is comprised of individual small stacks, thealternate ones of such stacks being offset with respect to the nextadjacent stack and alternate ones of the in-

